Ah well alrighty then. If you promise to read my links in the previous post 
No promises though, but it compiles here without errors.
const int ledPinR = 9;
const int ledPinG= 11;
const int ledPinB = 10;
const int buttonPin1 = 3;
int buttonState1 = 0;
byte redPwr = 0;
byte greenPwr = 0;
byte bluePwr = 0;
void fade(int, int, int, int); // forgot to mention you must declare a function prototype first (I think), or simply put the hole function here.
void setup()
{
pinMode(ledPinR, OUTPUT);
pinMode(ledPinG, OUTPUT);
pinMode(ledPinB, OUTPUT);
pinMode(buttonPin1, INPUT);
}
void loop()
{
buttonState1 = digitalRead(buttonPin1);
if (buttonState1 == LOW){
delay(200);
redPwr = 246;
greenPwr = 235;
analogWrite(ledPinR, redPwr);
bluePwr = 0;
analogWrite(ledPinG, greenPwr);
analogWrite(ledPinB, bluePwr);
fade(redPwr,greenPwr,bluePwr,25);
delay(500);
}
else {
analogWrite(ledPinR, LOW);
analogWrite(ledPinG, LOW);
analogWrite(ledPinB, LOW);
}
}
void fade(int redFrom, int grnFrom, int bluFrom, int delayTime)
{
for (int r=redFrom, g=grnFrom, b=bluFrom; r>=0; r-=5, g-=5, b-=5)
{
digitalWrite(ledPinR, r);
digitalWrite(ledPinG, g);
digitalWrite(ledPinB, b);
delay(delayTime);
}
}
Note: Regarding the function declaration (the line "fade(int, int, int, int);" at the top, I'm not sure if it is a must after all - it compiles without it.